无储能光伏逆变器多模态运行与并离网切换策略研究

Research on multi-mode control and seamless transfer strategy between grid- connected and islanding operation of PV inverter without energy storage

随着我国能源转型以及“双碳”目标的提出,分布式光伏装机量不断上升,其对电网的主动支撑控制技术是近来研究的热点问题。当分布式光伏工作在失去电网或储能支持的极端模态时,需要切换至无储能孤岛模态,采用电压型控制策略独立支撑电压。其中,实现光伏逆变器在并网运行模态与无储能孤岛模态之间的平滑切换,对于在失去电压同步信号后,仍能保证负载的不间断供电具有重要意义。因此,本文研究无储能光伏逆变器多模态控制策略,并提出了一种无储能光伏逆变器并离网平滑切换策略,该策略可以维持光伏逆变器在并网运行模态与无储能孤岛模态下的稳定运行,并能实现在两种模态之间的平滑切换,保证了光伏逆变器和负载之间的功率平衡。最后,实验结果验证了该方案的有效性,保证了含分布式光伏的配电网在多种模态下的供电品质。

With the change of China's energy policy and the proposal of “double carbon” goal,the installed capacity of distributed PV is increasing and the active support of distributed PV has become a research hotspot.When distributed PV works in the extreme mode of losing the support of power grid or energy storage,the distributed PV needs to switch to the islanding state without energy storage and adopt the voltage controlled strategy to support the voltage independently.Among them,the smooth switching of PV inverter between grid connected mode and islanding mode without energy storage is of great significance to ensure the uninterrupted power supply of load after the loss of voltage synchronization signal.Therefore,this paper studies the multi-mode control strategy of PV inverter without energy storage,and proposes a seamless transfer strategy between grid-connected and islanding operation of PV inverter.This strategy can maintain the stable operation of PV inverter in grid connected mode and islanding mode without energy storage,realize the smooth switching between the two modes,and ensure the power balance between PV inverter and load.Finally,the simulation and experimental results verify the effectiveness of the control method and ensure the power supply quality of the distribution network with distributed PV under multiple modes.